Place the sugar and egg yolks in the top of a double boiler and mix thoroughly. Add the hot milk and mix well again. Cook over hot water, stirring often, until the mixture is thick and creamy. Pour this custard through a fine sieve and let it cool.

Melt the chocolate over hot water in the top of the double boiler. Add the butter and stir until well blended. Pour the chocolate into the cooled custard and beat with a rotary beater until smooth.

Line the sides and bottom of a buttered 6-cup mold with the ladyfingers or macaroons. Gently pour the chocolate cream into the mold. Cover the top with more ladyfingers or macaroons and a sheet of foil. Refrigerate for 8 to 24 hours. To serve, unmold and garnish with chocolate curls.